Chondroitin-based nanoplexes as peptide delivery systems – Investigations into the self-assembly process, solid-state and extended release characteristics

Abstract

A new type of self-assembled polyelectrolyte complex nanocarrier composed of chondroitin 18 (CHON) and protamine (PROT) was designed and the ability of the carriers to bind salmon 19 calcitonin (sCT) was examined. The response of sCT-loaded CHON/PROT NPs to a change in 20 the properties of the liquid medium, e.g. its pH, composition or ionic strength was studied and in 21 vitro peptide release assessed. The biocompatibility of the NPs was evaluated in Caco-2 cells. 22 CHON/PROT NPs were successfully obtained with properties that were dependent on the 23 concentration of the polyelectrolytes and their mixing ratio. X-ray diffraction determined the 24 amorphous nature of the negatively charged NPs, while those with the positive surface potential 25were semi-crystalline. sCT was efficiently associated with the nanocarriers (98-100%) and a 26 notably high drug loading (13-38%) was achieved. The particles had negative zeta potential 27 values and were homogenously dispersed with sizes between 60 and 250 nm. CHON/PROT NPs 28 released less than 10% of the total loaded peptide in the first hour of the in vitro release studies. MEM -Eagle's Minimal Essential Medium 67MMR -mass mixing ratio 68 MPS -mean particle size 69MTS -3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium 70 MWCO -molecular weight cut-off 71 NP -nanoparticle 72 PBS -phosphate-buffered saline 73 PDI -polydispersity index 74PROT -protamine 75 PXRD -powder X-ray diffraction 76sCT -salmon calcitonin 77 Tg -glass transition 78 TR -transmittance 79ZP -zeta potential 80 81 Introduction 82Considerable efforts have been dedicated towards incorporation of bioactive ingredients into 83 nanoparticles (NPs) composed of biodegradable polymers (Hamidi et al., 2008). There are a 84 considerable number of polymers and techniques that are used to produce NPs, which allows a 85 broad differentiation of their internal and external structures as well as composition and biological 86properties. The choice of the nanoparticle manufacturing method is influenced by the solubility of 87 the active compound to be associated/complexed with the NPs as well as the solubility, chemical 88 structure, characteristic chemical groups, molecular weight and crystallinity/amorphicity of the 89 polymer (des Rieux et al., 2006). The most commonly used polymers are polyesters (e.g. 90 5 poly(lactic acid) and poly(lactic-co-glycolic acid)), either alone or in combination with other 91 polymers (des Rieux et al., 2006). However, the limitation of biodegradable water-insoluble 92 polymers is that they are mostly hydrophobic, whereas nucleic acids, many peptides and proteins, 93 which are recognised to have a great potential in therapeutics, are hydrophilic. This leads to 94 difficulties for the drug to be efficiently encapsulated (Sundar et al., 2010). Hence, the preparation 95 of NPs with the employment of more hydrophilic and naturally occurring polymers has been 96 explored. Among polymeric NPs, those composed of polyelectrolytes (polyelectrolyte complex ...

Freeze drying of polyelectrolyte complex nanoparticles: Effect of nanoparticle composition and cryoprotectant selection

“…All NPs were synthesised using a surfactant-and solvent-free polyelectrolyte complexation in an aqueous media as previously described (Umerska et al, 2017(Umerska et al, , 2015(Umerska et al, , 2014b(Umerska et al, , 2012.…”

“…Non-associated sCT was separated from nanoparticles by a combined ultrafiltrationcentrifugation technique (Centriplus YM-50, MWCO of 50 kDa for HA-based NPs or Amicon Ultra-15, MWCO of 30 kDa for CHON-based NPs; Millipore, USA) using a validated technique as described before (Umerska et al, 2015(Umerska et al, , 2014b(Umerska et al, , 2014a. The quantity of total and nonassociated sCT was measured by an isocratic HPLC method presented previously (Umerska et al, 2014b).…”

“…DSC experiments were conducted using a Mettler Toledo DSC 821 e with a refrigerated cooling system (LabPlant RP-100, UK), according to the method presented by Umerska et al (2015). Nitrogen was used as the purge gas.…”

Synergistic interactions between antimicrobial peptides derived from plectasin and lipid nanocapsules containing monolaurin as a cosurfactant against <em>Staphylococcus aureus</em>

“…AP114 and AP138 showed comparable adsorption yield, which can likely be attributed to their similar composition and physical properties. Although the interactions between the peptides and the nanocarriers are governed mainly by electrostatic forces, 30,31 it is possible to achieve significant adsorption of peptide onto LNCs even without the presence of an ionizable surfactant because of the enormous surface area of the nanocarriers and of the …”

“…22 A peptide loading of 1.5% or even 2.7% can be considered as high for lipidic nanocarriers -they are usually characterized by smaller loading of molecules than the nanocarriers made of hydrophilic polymers encapsulating the drug based on electrostatic interactions. 30,31 The DL is a key parameter when developing an effective nanoparticulate delivery system, because low loading may limit the use of nanoparticulate systems because a substantial amount of the formulation must be administered to achieve the therapeutic effect. 32 …”